@Dougkerr : At the first glance your calculation is right, i've found the same result of 14.2mm when i did ot the first time too. I've redone the calculation a second time (after the measuring the distance between the mount and the mirror in upper position on my rebel) and i've found 12.8mm (which approximately matches the adapter lenght and the spacing between mount and mirror in a rebel).

I'm not sure I follow. Are you trying to determine the flange back distance of an EOS body? That is known to be 44.00 mm.

Or were you trying to determine the thickness of the adapter from the patent drawing? I scaled it from the inside diameter of the flange ring on the front of the adapter, assuming it to be the same as the corresponding distance on an EOS mount (which is 54.0 mm).

That gives me a flange-face-to-flange-face thickness for the adapter of approximately 14.2 mm.

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- The pin connectors on the newer mount side are the same as EF's ones, they just added 3 extra pins, so the communication protocal would be same as EF.

The patent says that when using the "new" lenses" the protocol would be a new one, but when an EF lens was attached through a (passive) adapter, the body would use the EF protocol.

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- The pin connectors are located on the right side of the camera and vertically mounted.

The (entire) point of the patent is that if the contact block on the new body were put at 6 o'clock, things in that area of the adapter would be very congested, so it would be desirable on the new body to have the contacts either at 12 o'clock or at 9' o'clock (as would be seen looking at the face of the camera). Both these situations are shown in figures in the patent.

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- The new mount will have a 12.8mm shorter register than EF.

Not by my reckoning. How did you get that value?

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PS: I apologize for my scholar english, english is not my first language.

Jonathan

The first time i've done the measurement between 33a and 31a, and i've found 14.2mm like you.But if you look closely to the diagram, i suppose it will create a tiny gap of a few millimeters. So i redone the calculation, suposing the adapter would "embrace" the new mount "gapless". It gives approximately 12.8~13mm

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- The pin connectors on the newer mount side are the same as EF's ones, they just added 3 extra pins, so the communication protocal would be same as EF.

I suppose they would "mimick" what olympus did with their "passive" 4/3 to micro4/3 adapter.

The first time i've done the measurement between 33a and 31a, and i've found 14.2mm like you.But if you look closely to the diagram, i suppose it will create a tiny gap of a few millimeters.

I'm not sure what you mean.

In any case, the back face of the EF lens would contact surface 33a, and face 31a would contact the face of the "new body" mount (the face that, on an actual EOS mount, corresponds to surface 33a of the adapter).

Note that in the rear view that ring 31 has two contacting ribs on its outer and inner edges, exactly as we see on the rear of an EF lens (they touch surface 33a).

The four screws seen on the rear view are "between" those ribs, actually invading them a little. It is just like that on the rear of an EF lens (at a slightly larger diameter, of course).

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So i redone the calculation, suposing the adapter would "embrace" the new mount "gapless". It gives approximately 12.8~13mm

I don't follow your vision of the coupling. As I said above, as I see it, the back face of the EF lens would contact surface 33a, and face 31a would contact the face of the "new body" mount (the face that, on an actual EOS mount, corresponds to surface 33a of the adapter).

Do you not agree that the distance from surface 33a to surface 31a appears to be about 14.2 mm?

At the arbitrary scale at which I worked, the distance across the inner diameter of the front flange of the adapter (the circle that lies just inside the heads of the four cross-head screws) measured 1.981". I have no reason to believe that this face is any different than the mount on my EOS 40D (it looks exactly like the picture). There, that actual diameter is 54.0 mm.

In my workspace, the distance between surfaces 33a and 31a is 0.520". Thus, the real-size thickness of the mount would be 14.17 mm.

Certainly, the face of the "new" mount that surface 31a contacts is the reference datum from which the back flange is defined. (In the case of the EOS/EF mount, it is measured from the equivalent of surface 33a on the adapter.

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- The pin connectors on the newer mount side are the same as EF's ones, they just added 3 extra pins, so the communication protocal would be same as EF.

As I said, the patent says that with a "new" lens the protocol is different from the EOS/EF protocol, but that when an EF lens was attached, the body would use the old protocol.

For further reference, in US Patent application 2011/0052185 (in which the figures seem to be identical to that shown for the Japanese application), the text discusses that the difference between the flange back of the "new" body and the flange back of the "current" [EOS] body is equal to the "thickness" of the adapter, "C", of which they then say (with respect to Figure 2):

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The thickness is adistance in the direction of the optical axis from the camerabody side installation surface 31a to the lens side installationsurface 33a

Jonathan

I meant that the inner portion ( where the screws are mounted) of the new mount side of the adapter, slightly protudes from the outer portion of the adapter (new mount side) Ã la or much like the canon FD lenses where the rear element portion of the lenses protudes and goes into the camera body.

We don't have many informations about the new camera mount, toward the new camera body female bayonet.

Considering that Canon EOS and Canon FD flange back were expressed in millimeters and were exact numbers, respectively 44mm and 42mm; i guess it will be an exact number for the new mount too.

It means 12mm or 14mm for the adapter length.

* A 12mm adapter means that an APS-C size mirror box could fit, but in a very tight fit.(I made measurement on my rebel, measuring the distance between the EF mount and the mirror at it uppest possition when it lays flat under the viewfinder with the Bulb mode. I've found a little less than 12mm, in reality something much close to 11.5mm.) That's why i guessed the adapter could measure 12mm, i thought Canon would keep the mirror but i've realized in the patent that they won't.

So you're right, the most likely adapter length would be 14mm.

* A 14mm adapter means (as expressed in the patent) that an APS-C size mirror box won't fit at all.=> It's really a mirrorless camera, because they mention the lack of a mirror and its associated Phase Detection AF device in the new mount.Furthermore, we don't have any specs about sensor size. Without a mirror they would put anything they want. It could be Full Frame 24x36, Canon APS-H, APS-C size or even smaller than APS-C. After all the adapter is made for APS-C EFS lenses...so APS-C is the most likely.

From this point, we can say unanimously that new mount flange back distance will be exactly 30mm (44-14=30).

=> The new camera will NOT BE a kind of fusion between an EOS RT (OVF with fixed pellix mirror) and a small mirrorless camera such as a samsung nx, even with the addition of the OVF.It could have been interesting for me, but some user at the time of the EOS RT repported the lack of incoming light and flare/ghosting issues due to pellix mirror. EOS RT wasn't a succes. I think that's why Canon doesn't want to do the same mistake again.

In fact, there is only one way to follow for Canon. The mirrorless offering is already quite huge: * Olympus/panasonic Âµ43 * Samsung NX * Sony Nex * The future Nikon mirrorless with 16mm diagonal length sensor (x2.7 crop factor)

After the huge enthusiasm around the Fuji X100 and the hard beginning of Sony nex (only 3 lenses available), i bet that Canon will release a RANGEFINDER APS-C based sytem !!!

A 30mm flange back is close to other RF flange back of the past such as Contax G&RF and Nikon RF...

This new canon Digital RF sytems would sit right beetween high end compact camera (Canon G12) and bigger entry level DSLR (canon eos rebel/xxxd) in term of compactness.For the price this won't be that simple...i let you imagine the price.This new sytems could be a poor's man leica M RF competitor of the digital era (with liveview and AF). We could expect it would cost something between 1000~2000â‚¬.

[0004]In response to the desire to decrease the size and weight of digital single reflex lens cameras, in recent years a new type of single lens reflex camera that differs from the conventional single lens reflex camera has been proposed. The new type of single lens reflex camera is not provided with a quick return mirror for guiding the imaging light flux to a viewfinder, and the flange back is shorter than that of a conventional camera. The new type of interchangeable lenses having a short flange back that is compatible with this new type of camera has been proposed. However, these new type of interchangeable lenses cannot easily handle a variety of photographic conditions because there are few models. Therefore, there are cases in which it is desirable to use in the new type of camera the conventional type of interchangeable lenses that have already been introduced to the market and for which there are ample models and quantities. Thus, a conversion adapter for connecting the conventional type of interchangeable lenses with the new type of camera body is necessary. The functions required of this conversion adapter generally include matching the differing mounting profiles of the lenses and the camera body, matching the differing flange backs of the lenses and the camera body, and not hindering the communication system between the lenses and the camera body.

Not that it matters much, but I have spoken of the flange back for the Micro Four Thirds system as "20 mm", whereas I see it often described as "about 20 mm" (no definitive value being cited).

There is a report from a fellow who, from a a T mount-to-Lumix DMC-G1 adapter, concludes that the Micro Four Thirds flange back is likely about 19.2 mm (recognizing that the adapter might have an offset for "safe infinity focus" built in, so perhaps the actual nominal flange back is a little larger than that).

Thus it might be that the nominal flange back for the Micro Four Thirds system is exactly half that for the Four Thirds system (which has been stated as 38.67 mm), or 19.33 mm.

The EOS line has to date had three nominal frame sizes. It might be that the New Canon Thing (NCT) would also embrace bodies of differing format size, with something like 27 x 18 mm (32.44 mm image circle requirement) being the largest (0.75 of full-frame 35-mm format).

Then the "smaller" bodies might in fact have the rumored 18 x 12 mm format (0.50 of full-frame 35-mm format).

That would be a 3:2 ratio between the format sizes in the family, probably a sensible spread.

I have made no attempt to ascertain the design limits relating image circle to to such things as mount throat and back flange distance, so I'm in no position to opine on the design credibility.

You earlier suggested that you believe the mount implied by the patent would not support a frame size larger than what you call "APS-C" (by which I assume you don't actually mean the APS-C frame size but rather the Canon "1.3x" frame size often spoken of as "APS-C", perhaps nominally 22.3 x 14.9 mm). (The APS-C frame is 23.4 mm x 16.7 mm.)

You earlier suggested that you believe the mount implied by the patent would not support a frame size larger than what you call "APS-C" (by which I assume you don't actually mean the APS-C frame size but rather the Canon "1.3x" frame size often spoken of as "APS-C", perhaps nominally 22.3 x 14.9 mm). (The APS-C frame is 23.4 mm x 16.7 mm.)

Best regards,

Doug

Doug, I think you have a Typo in there, 1.3X crop APS-H is about 27.9 X 18.6 (1D MK IV) while 1.6X crop APS-C runs about 22.3 X 14.9.